Passenger traffic at Dallas Love Field probably will increase by nearly 50 percent after a federal law restricting flights out of the airport expires in October, the city’s aviation director predicted Friday.

Mark Duebner, speaking to the Rotary Club of Park Cities, said officials had predicted in 2008 that about 5.8 million people would board airplanes annually after the Wright amendment ended. That compares with about 4.2 million who flew out of Dallas in 2013.

“However, with the new [airline] schedules, the new projections, as we get closer we’re revising that up to over 6 million enplanements, almost a 50 percent increase of passengers at Love Field,” Duebner said.

The Wright amendment, passed more than 34 years ago by Congress, restricts nonstop service from Love Field to airports in Texas and eight other states. Congress amended the law in 2006 to allow passengers to connect to cities beyond the Wright amendment borders.

More important, lawmakers embraced a compromise among Southwest Airlines Co., American Airlines Inc., the cities of Dallas and Fort Worth and Dallas/Fort Worth International Airport to do away with the law entirely on Oct. 13, 2014. After that, airlines can fly nonstop anywhere in the United States out of Dallas.

In preparation for the law’s expiration, Dallas is replacing old gates at Love Field with a new 20-gate terminal. Twelve gates, occupied by Southwest, opened in 2013. The eight others are to open by Oct. 13.

Dallas-based Southwest will operate from 16 gates, and United Airlines Inc. will occupy two. Virgin America Inc. last month won permission to sublease the other two gates from American.

“With the arrival of Virgin and a more full utilization of those gates that used to be with American, that should add maybe another half million” passengers, Duebner said. “We’ve got a tidal wave of folks coming into the airport. We’re doing everything we can to prepare for that.”

Offering a cautious view about the effect of opening up Love Field was economist Bernard Weinstein, associate director of the Maguire Energy Institute and adjunct professor of business economics at SMU.

“In reality, the passenger air transportation market in D-FW is much more concentrated than it was 20 years ago and probably less competitive — indeed, maybe less competitive — than it’s ever been,” Weinstein said. “Now, I understand we’ve had bankruptcies and we’ve had consolidations. There are a lot of things going on out there in the market. But we still have pretty high air fares.”

He added later: “Don’t misunderstand me. I’m glad to see the Wright amendment go away. But in terms of improving the competitiveness in the North Texas air passenger market, I don’t think it’s any big whoop.”

Duebner said the city is looking at ways to improve the streets around Love Field and parking inside the airport to handle the expected increase in passengers.

“The Mockingbird-Cedar Spring interchange is of great concern. Mockingbird is a tough road already, and with the passenger loads and counts we’re looking at, we’re going to have some real impacts,” he said.

In answer to a question, Duebner said the airport needs more parking spaces.

“Holiday season, even this year, we’re going to be maxed out on parking,” he said. “We’ve begun the process of figuring out how we can build more structured parking.”

Work on the new terminal has upset many Love Field neighbors because the first 12 gates to open were closer to the east runway that parallels Lemmon Avenue. That put many more flights on that runway and in the sky over unhappy neighborhoods that didn’t like the increased activity overhead.

Asked if the city will put more flights on the west runway near Denton Drive and away from the neighborhoods, Duebner said that is beyond the city’s power.

“There isn’t an agreement, and we don’t have the ability to restrict flights off either runway. They’re open and available to pilots when they need them,” he said. “That being said, we’ve got pledges by all the airlines, Virgin and Southwest, that they will use — especially in the evening — the Denton side primarily.”

But noise levels overall have dropped, he said. A 1990 federal law required all U.S. commercial airplanes to meet Stage 3 noise limits by the end of 1999, and airplane engines keep getting progressively quieter as new airplanes replace older models.

Duebner noted that even as passenger totals have increased, total takeoffs and landings at the Dallas airport have declined.

In 1996, for example, the airport had 222,726 takeoffs and landings, including 99,571 by airlines. In 2013, the total had dropped to 177,417, including 88,028 by airlines. The biggest drop came in general aviation, which fell from 95,620 takeoffs and landings in 1996 to 55,122 last year.